An apparatus (appropriately described as a monitoring apparatus below) of monitoring an operation state of a system or a network has been proposed. The monitoring apparatus, for example, obtains communication packets (appropriately described as packets below) flowing in a network, and analyzes the obtained packets.
The monitoring apparatus obtains packets from a capturing point provided at a location through which packets to be analyzed pass. Such capturing points are generally provided at a plurality of locations in order to enable comprehensively-obtaining of packets to be used for analysis.
When the capturing points are provided at the plurality of locations, a packet may pass through a plurality of capturing points. In this manner, if the packet passes through the plurality of capturing points, the monitoring apparatus obtains a plurality of the same packets and thus it may be analyzed that the same packets are generated a plurality of times.
The monitoring apparatus may not calculate the number of packets with accuracy when the monitoring apparatus performs analysis under such a condition. In addition, when the monitoring apparatus performs analysis, the monitoring apparatus may determine that retransmission has been performed due to, for example, occurrence of packet loss. When such an analysis is performed, accuracy of the analysis is degraded.
Thus, the monitoring apparatus performs duplication determination on each of a plurality of obtained packets and detects a duplicate packet (also referred to as the same packet). The duplication determination is determination whether or not packets are duplicated. When the monitoring apparatus detects the duplicate packet, the monitoring apparatus deletes (also referred to as discard) the detected duplicate packet and analyzes a plurality of obtained packets other than the detected duplicate packet. Examples of the related art include International Publication pamphlet No. WO 2010/086907, Japanese Laid-open Patent Publication No. 2007-274332, and Japanese Laid-open Patent Publication No. 2008-211682.